Prior art conveyor systems for carrying open-ended hollow articles such as bottles from an input station through one or more processing stations to an output station have employed a variety of holding devices. Typically, a plurality of holding devices are carried and guided along a path through the various stations by a chain conveyor. At the input and output stations, provision is made for engaging and disengaging the articles with respect to the holding devices.
For many processes it is necessary for the holding device to internally engage the hollow article. Holding devices designed to internally engage a hollow article are herein referred to as internal holding devices. Prior art internal holding devices have employed chucks including a plurality of jaws or fingers that may be radially contracted to permit insertion of the jaws through an open end of the hollow article. Once inserted, the jaws are expanded radially to engage the interior of the article. When expanded, the jaws mechanically and/or frictionally engage the interior surface of the article to hold the article to the holding device.
Notwithstanding the variety of holding devices known in the prior art, the demands of present and future manufacturing processes demand or will demand new and improved holding devices that overcome one or more problems that arise when using previously known holding devices. One present day manufacturing process requires, for example an internal holding device that preferably can accommodate a relatively wide range of sizes and configurations of open neck bottles, including bottles having relatively small diameter neck openings. Many internal holding devices in the prior art have been found to be unsuitable because of limitations arising from their use of a pin-cam for urging the jaws radially outwardly. Internal holding devices of this type are described in U.S. Pat. Nos. 2,882,061, 3,545,803, 4,086,999, 4,291,910 and 4,572,355. Conventional pin-cam chuck mechanisms have not been found to be satisfactory for accommodating a wide range of neck opening sizes and configurations including relatively small diameter neck openings on the order of 1/2", coupled with adequate strength and holding characteristics especially in high temperature environments as may be found in processes where the containers are passed through ovens maintained at elevated temperatures. Many internal holding devices that have been previously proposed have parts inside the container that could become loose and fall off into the bottle.